JP2012040473A - Filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new filter by which treated water can be quickly taken after starting operation and the water taking amount of the treated water per unit time can be set more than the supplying amount of raw water per unit time.SOLUTION: The ice storing chamber 2 is arranged in the position above the filtering chamber 4, the treated water becoming excessive amount to the capacity of the lower filtering chamber 42 is stored in the ice storing chamber 3 in series, the treated water stored in the ice storing chamber 3 is returned into the lower filtering chamber 42 via the water collecting pipe 8 by the difference between the water taking amount and the supplying amount in the case the water taking amount of the treated water per unit time exceeds the supplying amount of the raw water per unit time.

Description

  The present invention relates to a filtration apparatus that obtains treated water by filtering raw material by passing it through a filter medium.

  As a filtration device that passes the raw water through the filter medium and obtains treated water, a filtration device equipped with a water storage chamber at the top of the filtration chamber and having the function of backwashing the filter medium with the treated water stored in this water storage chamber (backwash water self A holding pressure filter has been developed (for example, see Patent Document 1 below).

  As shown in FIG. 5, in the filtration device 100 described in Patent Document 1, first, the raw water is opened to the upstream portion 141 of the filtration chamber 14 through the raw water supply pipe 16 by opening the raw water electric on-off valve 161. Supply. The raw water supplied to the upstream part 141 of the filtration chamber 14 is filtered by passing through the filter medium tank 15 from the upstream part 141 toward the downstream part 142 and becomes treated water. The treated water is transported to the water storage chamber 13 through the water collecting pipe 18 and is sequentially stored in the water storage chamber 13.

  One end of the treated water water pipe 17 for taking treated water from the water storage chamber 13 (open end 171 on the inlet side of the treated water) is opened in the upper part of the water storage chamber 13 through the wall surface of the filtration device 100. . Thus, the treated water transported to the water storage chamber 13 is stored in the water storage chamber until the water level in the water storage chamber 13 reaches a position exceeding the opening end 171 of the treated water supply pipe 17. The amount of treated water that exceeds the position of the open end 171 of the treated water supply pipe 17 flows into the treated water discharge pipe 17 from the open end 171 of the treated water supply pipe 17, and is filtered through the treated water supply pipe 17. Supplied automatically outside.

  Further, in the filtration device 100 described in Patent Document 1, when the filter medium tank 15 is backwashed, the raw water electric on-off valve 161 is closed and the backwash electric on-off valve 191 is opened to store water in the water storage chamber 13. The treated water that has been returned is returned to the downstream portion 142 of the filtration chamber 14. The treated water returned to the downstream part 142 of the filtration chamber 14 passes through the filter medium tank 15 from the downstream part 142 toward the upstream part 141 to backwash the filter medium tank 15. The water after backwashing is discharged through the backwash water distribution pipe 19 together with the dirt pushed out from the filter medium tank 15 by backwashing.

  That is, the filtration device 100 described in Patent Document 1 uses the treated water stored in the water storage chamber 13 as backwash water for backwashing the filter medium 15, and opens the treated water supply pipe 17. By opening the end 171 in the upper part of the water storage chamber 13, a constant amount of treated water is always stored in the water storage chamber 13.

Japanese Unexamined Patent Publication No. 2000-1000079

  By the way, this type of filtration device is used for supplying treated water (in this case, filtered seawater) to a relatively large aquarium (ginger) used, for example, in fish riverbanks.

  On the fish bank, etc., it is difficult to predict the time when the live fish will be landed due to changes in the weather, etc., but it is necessary to put the live fish purchased into the cage as soon as possible. In some cases, it may be necessary to completely replace the water in the ginger in a short time, and the filtration device used is required to have a processing capability that can fill the ginger in a short time depending on the situation.

  However, in the filtration device described in Patent Document 1, the treated water cannot be taken in unless the water level of the treated water in the water storage chamber rises to a position exceeding the open end of the treated water supply pipe extending to the upper portion of the water storage chamber. Therefore, it takes a long time for the water to be taken after the operation is started.

  Moreover, in the filtration apparatus described in patent document 1, the intake amount of the treated water per unit time cannot be set more than the supply amount of the raw water per unit time.

  This is because, in the filtration device described in Patent Document 1, the portion of the treated water stored in the water storage chamber that exceeds the position of the open end of the treated water supply pipe sequentially flows into the open end. Therefore, the water level of the treated water existing in the water storage chamber is always near the open end of the treated water supply pipe. Therefore, if water is forcibly taken using a suction pump or the like, the level of the treated water immediately existing in the water storage chamber is lowered from the position of the open end of the treated water supply pipe, and water cannot be taken.

  Therefore, in the filtration device described in Patent Document 1, in order to increase the intake amount of treated water per unit time, it is necessary to increase the supply amount of raw water per unit time.

  However, in the filtration device described in Patent Document 1, in order to increase the intake amount of treated water per unit time by increasing the supply amount of raw water per unit time, both the filtration chamber and the water storage chamber are provided. It is necessary to make the pressure vessel in a sealed state, and in order to ensure rigidity, the range of selection of materials is narrowed and the cost is increased.

  The present invention has been developed to solve the above technical problem, and can take up treated water immediately after the start of operation, and the amount of treated water taken per unit time can be reduced per unit time. It aims at providing the novel filtration apparatus which can also be set more than the supply amount of raw | natural water.

  The filtration device of the present invention includes a hollow filtration tank, a partition partitioning the inside of the filtration tank into a water storage chamber on the upper side and a filtration chamber on the lower side, an upper filtration chamber on the upper side, and a lower lower portion on the filtration chamber While being connected to the upper filtration chamber through the filter medium disposed at the position partitioned into the filtration chamber, the wall of the filtration tank, and the raw water supply pipe opening toward the upper filtration chamber, and the lower filtration chamber through the wall of the filtration tank A water intake pipe that opens toward the lower filtration chamber, and a water collection pipe that opens at one end toward the lower filtration chamber and opens at the other end toward the water storage chamber.

  In the filtration device of the present invention, the raw water supplied to the upper filtration chamber via the raw water supply pipe passes through from the upper part of the filter medium toward the lower part and becomes treated water and is stored in the lower filtration chamber. The treated water is taken from the room through the intake pipe.

  That is, in the filtration device of the present invention, treated water can be stored in the lower filtration chamber, and treated water can be taken directly from the lower filtration chamber, so the time required from the start of operation of the filtration device until water can be taken. Will be very short.

  And in the filtration apparatus of this invention, when the intake amount per unit time of treated water is smaller than the supply amount per unit time of raw water (including the case where the intake amount is zero), the capacity of the lower filtration chamber The excessive amount of treated water is transported to the water storage chamber via the water collection pipe by the supply pressure of the raw water and stored.

  On the other hand, when the amount of treated water taken per unit time exceeds the amount of raw water supplied per unit time, the treated water stored in the water storage chamber is treated with the water level of the treated water stored in the water storage chamber and the collection pipe. It is returned to the lower filtration chamber through the water collection pipe by the water head pressure generated between the end opening position.

  That is, the filtration device of the present invention is configured to be able to take the treated water stored in the water storage chamber in addition to the treated water stored in the lower filtration chamber, so that the amount of treated water taken per unit time is a unit. Even when the supply amount of raw water per hour is exceeded, treated water can be stably obtained.

  In fact, among the treated water stored in the water storage chamber, the treated water that can be substantially used for intake is the collected water that opens toward the water storage chamber among the treated water stored in the water storage chamber. This is the amount of water stored beyond the opening position (hereinafter referred to as substantial water storage). Accordingly, in the present invention, by setting the opening position of the water collecting pipe that opens toward the water storage chamber as low as possible in the water storage chamber, the ratio of the substantial water storage to the treated water stored in the water storage chamber is improved. It is preferable to make it.

  The filtration device of the present invention preferably further includes a backwash discharge pipe communicating with the upper filtration chamber through the wall surface of the filtration tank and opening toward the upper filtration chamber.

  If this backwash on / off valve is provided, when the backwash on / off valve is opened with the supply of raw water and the intake of treated water stopped, the treated water stored in the water storage tank is lowered through the water collecting pipe. It is returned to the filtration chamber, passes from the lower part of the filter medium toward the upper part, and is discharged out of the filtration tank through the backwash discharge pipe. Thus, the filter medium can be backwashed with the treated water stored in the water storage chamber.

  According to the filtration device of the present invention, treated water can be taken immediately after the start of operation, and the amount of treated water taken per unit time can be set to be higher than the supply amount of raw water per unit time. Become.

FIG. 1 is a diagram schematically showing an embodiment of the filtration device of the present invention. FIG. 2 is a view showing an example of a strainer that constitutes a filter medium installation base in the filtration device, FIG. 2 (a) is a front view showing the right half of the strainer main body section in section, and FIG. It is a front view which shows the right half of a connection part in a cross section. FIG. 3 is a view showing a state in which the strainer is fitted to the installation base main body, FIG. 3A is a cross-sectional view showing a state in which the connecting portion is inserted into the installation base main body, and FIG. It is sectional drawing which shows the state which inserted the strainer main-body part in the connection part. FIG. 4 shows a filtration device in which (a) supply state of raw water, (b) intake state of treated water (amount of intake water <raw water supply amount), (c) intake state of treated water (amount of intake water> raw water supply amount), It is a schematic diagram which shows each state of (d) backwashing state, respectively. FIG. 5 is a diagram schematically showing a conventional filtration device.

  Hereinafter, an embodiment of the filtration device of the present invention will be described. The filtration device of the present invention is not limited to this embodiment.

  In FIG. 1, one Embodiment of the filtration apparatus of this invention is shown typically.

  The filtration device 1 according to the present embodiment includes a hollow cylindrical filtration tank 2, a partition wall 21 that divides the filtration tank 2 into an upper water storage chamber 3 and a lower filtration chamber 4, and the filtration chamber 4. Further, the filter medium 5 arranged at a position partitioned into an upper filtration chamber 41 on the upper side and a lower filtration chamber 42 on the lower side, and the upper filtration chamber 41 through the wall surface of the filtration tank 2 and toward the upper filtration chamber 41. The raw water supply pipe 6 that opens, the intake pipe 7 that communicates with the lower filtration chamber 42 through the wall surface of the filtration tank 2 and opens into the lower filtration chamber 42, and one end opens into the lower filtration chamber 42, A water collecting pipe 8 having the other end opened toward the inside of the water storage chamber 3 is provided.

  The filtration device 1 has a hollow cylindrical filtration tank 2 as a main body.

  The filtration tank 2 is partitioned into a water storage chamber 3 on the upper side and a filtration chamber 4 on the lower side by a partition wall 21 that divides the inside of the filtration tank 2 up and down.

  The water storage chamber 3 is provided with an opening 22 in the ceiling, and is designed so that the air pressure inside and outside the water storage chamber 3 is always equal. That is, since no extreme internal pressure is generated in the water storage chamber 3 in the filtration device 1 according to this embodiment, it is sufficient for the strength of the water storage chamber 3 to be rigid enough to store treated water. Thus, the outer wall of the water storage chamber 3 can be formed using a relatively inexpensive material such as plastic.

  On the other hand, the internal pressure of the filtration chamber 4 changes depending on the supply amount of raw water, the intake amount of treated water, the degree of clogging of the filter medium 5, and the like. For this reason, in this embodiment, the filtration chamber 4 is formed by FRP. In addition, the partition wall 21 that vertically partitions the interior of the water storage chamber 3 has a dome shape that gently swells upward from the peripheral portion toward the center portion, and rounds the corners of the bottom wall of the filtration chamber 4 to round the bottom of the filtration chamber 4. Improves pressure resistance. Further, the filtration chamber 4 is provided with a relief valve 43 that automatically opens when the internal pressure of the filtration chamber 4 exceeds an allowable level, and is controlled so that the internal pressure of the filtration chamber 4 does not become extremely large. ing.

  The filter medium 5 is a layer of sand laid on the filter medium mounting base 51 disposed in the filter chamber 4 so as to have a constant laminated thickness.

  The filter medium installation base 51 is obtained by fitting strainers 54 to a plurality of through holes 53 provided in a plate-shaped installation base main body 52.

  As shown in FIG. 2, the strainer 54 includes a strainer main body 55 (see FIG. 2A) and a connecting portion 56 (see FIG. 2B) that connects the strainer main body 55 to the installation base main body 52. .

  The strainer body 55 is a hollow member in which a hollow head 552 is connected to an upper opening end of a hollow cylindrical leg portion 551, and a lower opening end of the leg portion 551 is open.

  The head 552 has a hollow cylindrical peripheral wall 554 and a ceiling surface 555 that closes the upper end opening of the side wall, and a plurality of slits 553 are provided around the peripheral wall 554.

  The connecting portion 56 includes a hollow cylindrical connecting portion main body 561 and a flange portion 562 provided on the upper opening end periphery of the connecting portion main body 561. The outer diameter of the connecting portion main body 561 and the diameter of the through hole 53 provided in the installation base main body 52 are set to the same diameter. Further, the peripheral wall 564 of the connecting portion main body 561 is provided with a tapered shape in which the inner diameter gradually decreases toward the lower opening end. Furthermore, a cutout 563 is provided in the peripheral wall 564 of the connecting portion main body 561.

  As shown in FIG. 3, when the strainer 54 is fitted into the through hole 53 provided in the installation base main body 52, first, the connecting portion main body 561 in the connecting portion 56 is inserted into the through hole 53, and the flange portion 562 Push in until the upper surface of the installation base body 52 comes into contact. Next, the leg portion 551 in the strainer main body portion 55 is inserted into the connection portion main body 561 in the connection portion 56 (see FIG. 3A).

  The outer diameter of the leg portion 551 in the strainer main body 55 is set to be the same as the inner diameter of the upper opening end in the connecting portion main body 561, but the diameter of the side wall 564 of the connecting portion main body 561 is toward the lower opening end. Since the taper shape is reduced, the connecting portion main body 561 increases in diameter while expanding the notch 563 as the insertion of the leg portion 551 becomes deeper (see FIG. 3B). Thereby, the strainer 54 can be fitted into the through hole 53 provided in the installation base main body 52 without any gap.

  By the way, when sand is used as the filter medium 5, the sand does not fall into the lower filtration chamber 42 through the filter medium mounting base 51, and the backwash water rises uniformly over the entire surface of the filter medium 5 during backwashing. In order to assist, it is common to place gravel (supporting gravel) having a particle size larger than that of sand between the sand and the filter medium mounting base 51.

  In this embodiment, in this embodiment, a filter medium is installed by fitting a plurality of through holes 53 provided in the installation base body 52 with a strainer 54 provided with a slit 553 having a groove width smaller than the particle size of sand on the peripheral wall 554. Since the table 51 is used, the sand is prevented from passing through the filter medium installation table 51 and falling into the lower filtration chamber 42. In addition, since the slit 553 is provided on the side wall 554 of the strainer body 55, the backwash water diffuses by passing through the slit 553 during the backwashing and rises uniformly over the entire surface of the filter medium 5. From this, in this embodiment, it is not necessary to interpose support gravel. In the case where the supporting gravel is not interposed between the sand and the filter medium installation base 51, there is an advantage that the replacement work of the filter medium 5 becomes easy.

  The raw water supply pipe 6 includes a raw water opening / closing valve 61, and the raw water is supplied into the upper filtration chamber 41 through the raw water supply pipe 6 by opening the raw water opening / closing valve 61. Pumping of the raw water through the raw water supply pipe 6 is performed by a pump P. In the present embodiment, the open end 62 of the raw water supply pipe 6 that opens in the upper filtration chamber 41 is bent upward. Thereby, raw | natural water is discharged toward the upper direction of the upper filtration chamber 41, and falls sequentially, diffusing. That is, the raw water is prevented from being biased to a part of the filter medium 5.

  The intake pipe 7 includes a treated water opening / closing valve 71, and the treated water stored in the lower filtration chamber 42 is taken in via the intake pipe 7 by opening the treated water opening / closing valve 71.

  The water collecting pipe 8 is erected through the partition wall 21, the filter medium 5, and the filter medium installation base 51. The lower end of the water collecting pipe 8 that passes through the filter medium mounting base 51 and opens into the lower filtration chamber 42 is bent toward the periphery of the lower filtration chamber 42. Further, the position (height) of the upper end opening 81 of the water collecting pipe 8 that penetrates the partition wall 21 and protrudes into the water storage chamber 3 is set to be the position (height) of the top of the dome-shaped partition wall 21. ing.

  The filtration device 1 according to this embodiment further includes a backwash discharge pipe 9 provided with a backwash on / off valve 91 that communicates with the upper filtration chamber 41 through the wall surface of the filtration tank 2 and opens into the upper filtration chamber 41. It has.

  The backwash discharge pipe 9 passes through the partition wall 21, the filter medium 5, and the filter medium installation base 51 in the vertical direction along the central axis of the cylindrical filter tank 2, and is bent in the horizontal direction in the lower filtration chamber 42. It penetrates the wall surface of the tank 2 (the wall surface of the lower filtration chamber 42) and communicates with the outside. Note that the backwash discharge pipe 9 may penetrate the wall surface of the upper filtration chamber 41 and communicate with the outside without penetrating the partition wall 21, the filter medium 5, and the filter medium installation base 51.

  The upper end of the backwash discharge pipe 9 that protrudes through the partition wall 21 is closed, and a discharge port 92 that opens toward the inside of the upper filtration chamber 41 at a position near the lower surface of the partition wall 21 in the backwash discharge pipe 9. Is provided. An upper end portion of the backwash discharge pipe 9 protruding into the water storage chamber 3 communicates with an air vent valve 93 disposed on the outer wall of the filtration tank 2.

  As shown in FIG. 4A, in the filtration device 1 according to this embodiment, the raw water is supplied into the upper filtration chamber 41 by opening the raw water on-off valve 61 after operating the pump P. (Supply X is the amount of raw water supplied per unit time). The raw water supplied into the upper filtration chamber 41 is filtered by passing through the filter medium 5 from the upper part toward the lower part by gravity, and is stored in the lower filtration chamber 42 as treated water.

  At this time, the air vent valve 93 is opened, and the air accumulated in the upper portion of the upper filtration chamber 41 is sequentially discharged out of the filtration tank 2 through the discharge port 92 and the air vent valve 93. Thereafter, if the outflow of the raw water is confirmed from the air vent valve 93, it is determined that the air has sufficiently escaped, and the air vent valve 93 is closed.

  In this state, when the treated water on-off valve 71 provided in the intake pipe 7 is opened, treated water is taken from the lower filtration chamber 42 through the intake pipe 7 (the amount of treated water taken is Y). ).

  In other words, the filtration device 1 according to the present embodiment removes the treated water that has passed through the filter medium 5 and accumulated in the lower filtration chamber 42 from the lower filtration chamber 42 through the intake pipe 7 that is communicated with the lower filtration chamber 42. Can take water directly. Thereby, after the operation of the filtration device 1 is started (that is, after the raw water on-off valve 61 is opened), treated water can be taken in a relatively short time.

  Here, when the intake amount Y per unit time of the treated water is smaller than the supply amount X per unit time of the raw water (Y <X), as shown in FIG. The treated water that is excessive with respect to the capacity of the water is transported to the water storage chamber 3 through the water collection pipe 8 by the supply pressure of the raw water by the pump P, and stored. In the present embodiment, a drain pipe 31 having one end opened in the upper part of the water storage chamber 3 and the other end communicating with the outside of the filtration tank 2 is provided, and the stored treated water has exceeded a certain amount. In that case, excess treated water is discharged out of the filtration tank 2 through the drain pipe 31.

  On the other hand, when the intake amount Y per unit time of the treated water exceeds the supply amount X per unit time of the raw water (Y> X), as shown in FIG. Substantial water storage in the treated water is lowered through the water collecting pipe 8 due to the water head pressure generated between the water level of the treated water stored in the water storage chamber 3 and the position of the upper end opening 81 of the water collecting pipe 8. Returned to the filtration chamber 42.

  That is, in the filtration device 1 according to the present embodiment, the water storage chamber 3 is disposed at a position above the filtration chamber 4, and the treated water that is excessive with respect to the capacity of the lower filtration chamber 42 is sequentially stored in the water storage chamber 3. However, if the amount of treated water taken per unit time exceeds the amount of raw water supplied per unit time, the treated water stored in the water storage chamber 3 will flow through the collecting pipe 8 by the difference between the amount of water taken and the amount supplied. It is set as the structure returned in the lower filtration chamber 42 via. Thus, even when the amount of treated water taken per unit time exceeds the supply amount of raw water per unit time, the treated water stored in the lower filtration chamber 42 and the treated water stored in the water storage chamber 3 are stored. The treated water can be obtained stably until the substantial water storage inside is exhausted.

  Further, as described above, in the filtration device 1 according to the present embodiment, the position (height) of the upper end opening 81 of the water collecting pipe 8 penetrating the partition wall 21 and projecting into the water storage chamber 3 is defined as the dome-shaped partition wall. It is set to be the position (height) of the top of 21. That is, in the filtration device 1 according to the present embodiment, by setting the position of the upper end opening 81 of the water collecting pipe 8 as low as possible in the water storage chamber 3 (near the upper surface of the partition wall 21), The ratio of the substantial water storage amount with respect to the amount of treated water stored is improved so that the treated water stored in the water storage chamber 3 can be used without waste.

  As shown in FIG. 4D, when the raw water on-off valve 61 and the treated water on-off valve 71 are closed and the backwash on-off valve 91 is opened, the treated water stored in the water storage chamber 3 is transferred to the water storage chamber 3. The water head pressure generated between the water level of the stored treated water and the upper end opening 81 of the water collecting pipe 8 is returned to the lower filtration chamber 42 via the water collecting pipe 8. The treated water returned to the lower filtration chamber 42 passes from the lower part of the filter medium 5 toward the upper part, and passes through the backwash discharge pipe 9 from the discharge port 92 provided at the upper part of the backwash discharge pipe 9. Discharged outside. Thus, the filter medium 5 can be backwashed with the treated water stored in the water storage chamber 3.

  In addition, in the case where sufficient treated water is not stored in the water storage chamber 3 to backwash the filter medium 5, by stopping the intake of treated water while maintaining the supply of raw water prior to backwashing, A sufficient amount of treated water may be stored in the water storage chamber 3.

  In the present embodiment, the lower end of the water collecting pipe 8 that passes through the filter medium mounting base 51 and opens into the lower filtration chamber 42 is bent toward the periphery of the lower filtration chamber 42. The treated water returned to the lower filtration chamber 42 is diffused in the lower filtration chamber 42. Thus, the treated water passes through the entire surface of the filter medium 5 without unevenness.

  Further, in the present embodiment, the discharge port 92 is disposed at a position near the lower surface of the partition wall 21 (upper part of the upper filtration chamber 41), and the outlet side of the backwash water in the backwash discharge pipe 9 is connected to the lower filtration chamber 42. By providing, a level difference is provided between the discharge port 92 and the backwash water outlet side, and the backwash water flowing into the backwash discharge pipe 92 from the discharge port 92 is quickly discharged out of the filtration tank 2. Designed to be

  In addition, since the backwash water after backwashing rises in the upper filtration chamber 41 with the dirt adhering to the filter medium 5, by providing a plurality of discharge ports 92 in the backwash discharge pipe 92, the backwash water after backwashing is provided. It is preferable that the backwash water is introduced into the backwash discharge pipe 92 from multiple directions.

  The filtration device of the present invention can be suitably used when supplying treated water to a relatively large aquarium such as a fish river bank, an aquarium, or a pool.

DESCRIPTION OF SYMBOLS 1 Filtration apparatus 2 Filtration tank 3 Water storage chamber 4 Filtration chamber 5 Filter medium 6 Raw water supply pipe 7 Intake pipe 8 Water collection pipe 9 Backwash discharge pipe

Claims (2)

A hollow filtration tank;
A partition partitioning the inside of the filtration tank into an upper water storage chamber and a lower filtration chamber;
A filter medium disposed in a position dividing the filtration chamber into an upper filtration chamber on the upper side and a lower filtration chamber on the lower side;
A raw water supply pipe communicating with the upper filtration chamber through the wall of the filtration tank and opening toward the upper filtration chamber;
A water intake pipe communicating with the lower filtration chamber through the wall of the filtration tank and opening toward the lower filtration chamber;
A water collecting pipe having one end opened toward the lower filtration chamber and the other end opened toward the water storage chamber;
A filtration device comprising:
The raw water supplied to the upper filtration chamber through the raw water supply pipe passes through the filter medium from the upper part toward the lower part, and is stored as treated water in the lower filtration chamber, and is treated from the lower filtration chamber through the intake pipe. To take water,
If the amount of treated water taken per unit time is less than the amount of raw water supplied per unit time, the amount of treated water that is excessive relative to the volume of the lower filtration chamber is passed through the water collection pipe by the raw water supply pressure. Transported to the water storage room, stored,
If the amount of treated water taken per unit time exceeds the amount of raw water supplied per unit time, the treated water stored in the water storage chamber is treated with the water level of the treated water stored in the water storage chamber and the other end of the collecting pipe. A filtration device which is returned to the lower filtration chamber via a water collecting pipe by a head pressure between the opening position and the opening position. The filtration device according to claim 1,
Furthermore, the filtration apparatus which comprises the backwash discharge pipe which opens to the upper filtration chamber while communicating with the upper filtration chamber through the wall surface of the filtration chamber in the filtration tank.

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